Operating modes of Meanwell HLG transformers:
The well-known and proven Meanwell HLG power supplies can be adjusted or dimmed using a variety of different options. These are described below.
This is indicated by the last letter of the product designation. ( Marking "Z" in the example below: HLG-xxxH-yyZ)
An exception is the type without last letter after voltage specification (yy). This Meanwell power supply does not allow any adjustments, but offers IP67 protection.
Type A (e.g. HLG-240-12A):
Type A enables either constant current or constant voltage operation. This depends on the load and the setting via internal potentiometers, which are hidden behind small rubber covers of the Meanwell HLG for moisture protection.
- Constant voltage mode:
Via the controller Vo. ADJ. the output voltage can be set in a range around the nominal secondary voltage according to the data sheet (data sheet information: Voltage Adj. Range):
This voltage is maintained as long as the maximum current is not exceeded. Then the power supply unit switches to constant current operation.
- Constant current operation and works as a constant voltage source:
The controller Io. ADJ is used to set the maximum operating current. The Meanwell HLG goes into the current limit and acts as a constant current source.
However, this only works if the connected load is sufficiently low-resistance to the operating voltage. (Ohms Law), as is the case with LEDs.
Type B (e.g. HLG-185-12B)
Type B was specifically designed for the dimming operation of LEDs or LED modules / LED lamps. The special feature is its different possibilities for dimming.
In addition to the connection cables for mains input voltage (three-pole: green-yellow, brown, blue) and the output cable (red, black), the Meanwell HLG Type B also has a third connection cable with the colours (blue, white). This input enables dimming operation as described below.
- PWM (Puls width modulation):
A 10V control signal is connected to the input, whose pulse width ratio determines the output voltage of the power supply and thus the brightness of the connected LED lamps. (Attention: LED lamp must also be suitable for dimming operation).
For the provision of the PWM signal, there are various products on the market, which e.g. generate a PWM signal from phase angle dimming. Often different operating devices are controlled in parallel. Especially popular is the DAP-04 adapter from Meanwell, which functions as a DALI-PWM adapter and thus allows even the most powerful Meanwell transformers to be controlled via DALI.
The PWM ratio determines the output voltage as shown in the table below:
Usual PWM frequency between 100Hz and 3kHz.
- 1-10V Signal:
If a variable voltage of an external source between 1 and 10V is applied to the input, the output voltage changes according to the following table:
Important: Potential separation between the output voltage and the control voltage.
- Potentiometer control:
If a potentiometer, adjustable resistor is connected between 0 and 100KOhm, the output voltage can be assigned to the set resistance value in something like this.
If several devices are operated in parallel, use correspondingly lower resistance values.
Type C (e.g. HLG-320-24C)
Type C differs from Type A only in terms of connectivity. Instead of cables, the type C has a terminal block.